[Federal Register Volume 86, Number 33 (Monday, February 22, 2021)]
[Rules and Regulations]
[Pages 10444-10447]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-01823]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1109; Product Identifier 2020-NM-067-AD; Amendment 
39-21383; AD 2021-01-07]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-700 series airplanes. This AD 
requires repetitive testing to verify correct operation of the smoke 
clearance mode of the equipment cooling system and low pressure 
environmental control system, and corrective actions if necessary. This 
AD also requires installing new relays and changing the wiring to the 
environmental control system, among other actions. This AD was prompted 
by a determination that a repetitive test is needed to assess the 
components on airplanes equipped with a certain air distribution system 
configuration. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective March 9, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of March 9, 
2021.
    The FAA must receive comments on this AD by April 8, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this final rule, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; internet https://www.myboeingfleet.com. You may 
view this service information at the FAA, Airworthiness Products 
Section, Operational Safety Branch, 2200 South 216th St., Des Moines, 
WA. For information on the availability of this material at the FAA, 
call 206-231-3195. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
1109.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
1109; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this final rule, any comments received, and other information. The 
street address for Docket Operations is listed above. Comments will be 
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Susan L. Monroe, Aerospace Engineer, 
Cabin Safety and Environmental Systems Section, FAA, Seattle ACO 
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-
231-3570; email: susan.l.monroe@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA has determined that a repetitive test is needed to assess 
the components on airplanes equipped with a certain air distribution 
system configuration. A review by Boeing found that there was no 
maintenance procedure available to assess the components used to 
reconfigure the air distribution system to the cargo fire mode. Without 
the repetitive test, failures of components could be latent for 
extended periods. This condition, if not addressed, could result in 
latent failures of the equipment cooling system and low pressure 
environmental control system, which, in combination with a cargo fire 
event, could result in smoke in the flight deck and/or main cabin, and 
possible loss of aircraft control.

Other Related Rulemaking

    The FAA issued AD 2016-04-06, Amendment 39-18400 (81 FR 9756, 
February 26, 2016) (AD 2016-04-06), applicable to all The Boeing 
Company Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes. That AD requires doing repetitive testing to verify correct 
operation of the equipment cooling system and low pressure 
environmental control system, and corrective actions if necessary. That 
AD also requires, for certain airplanes, installing new relays and 
changing the wiring to the environmental control system. That AD was 
prompted by a determination that a repetitive test is needed to inspect 
the components on airplanes equipped with a certain air distribution 
system configuration. The actions required by that AD are intended to 
address latent failures of the equipment cooling system and low

[[Page 10445]]

pressure environmental control system, which, in combination with a 
cargo fire event, could result in smoke in the flight deck and/or main 
cabin, and possible loss of aircraft control.
    Since issuance of that AD, the FAA has determined that additional 
actions are necessary to address the same unsafe condition identified 
in AD 2016-04-06 for The Boeing Company Model 737-700 series airplanes 
having line numbers (L/Ns) 481, 545, 684, 979, 1089, 1211, and 1223. 
Those actions have been included in the revised service information 
specified in paragraphs (g) and (h) of this AD. This AD adds the 
requirements of paragraph (h) that include installing new relays and 
changing the wiring to the environmental control system, and 
accomplishing certain concurrent actions, for the affected airplanes.

Relationship Between This AD and AD 2016-04-06

    This AD does not supersede AD 2016-04-06. Rather, the FAA has 
determined that a stand-alone AD would be more appropriate to address 
the requirements of this AD. AD 2016-04-06 did not address the unsafe 
condition for the 7 airplanes mentioned previously and identified in 
paragraph (c) of this AD. To address the unsafe condition for these 7 
airplanes, this AD requires repetitive testing to verify correct 
operation of the smoke clearance mode of the equipment cooling system 
and low pressure environmental control system, and corrective actions 
if necessary; and also requires installing new relays and changing the 
wiring to the environmental control system, and accomplishing certain 
concurrent actions. As such, this AD terminates all of the requirements 
of AD 2016-04-06 for the airplanes identified in paragraph (c) of this 
AD only.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed the following service information:
    Boeing Alert Service Bulletin 737-26A1122, Revision 3, dated 
January 31, 2020. This service information describes procedures for 
installing new relays and changing the wiring to the environmental 
control system.
    Boeing Alert Service Bulletin 737-26A1137, Revision 2, dated 
January 27, 2020. This service information describes procedures for 
repetitive testing to verify correct operation of the smoke clearance 
mode of the equipment cooling system and low pressure environmental 
control system, and applicable corrective actions.
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in the ADDRESSES section.

FAA's Determination

    The FAA is issuing this AD because the agency evaluated all the 
relevant information and determined the unsafe condition described 
previously is likely to exist or develop in other products of the same 
type design.

AD Requirements

    This AD requires accomplishing the actions specified in the service 
information described previously.

FAA's Justification and Determination of the Effective Date

    There are currently no domestic operators of these products. 
Therefore, the FAA finds that notice and opportunity for prior public 
comment are unnecessary and that good cause exists for making this 
amendment effective in less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety and was not preceded by notice and an opportunity for public 
comment. However, the FAA invites you to send any written data, views, 
or arguments about this final rule. Send your comments to an address 
listed under the ADDRESSES section. Include Docket No. FAA-2020-1109 
and Product Identifier 2020-NM-067-AD at the beginning of your 
comments. The FAA specifically invites comments on the overall 
regulatory, economic, environmental, and energy aspects of this final 
rule. The FAA will consider all comments received by the closing date 
and may amend this final rule because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, as well 
as a report summarizing each substantive public contact with FAA 
personnel concerning this AD. The FAA will consider all comments 
received by the closing date for comments. The FAA may amend this AD 
because of those comments.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this AD contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this AD, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this AD. Submissions containing CBI should be sent to Susan 
L. Monroe, Aerospace Engineer, Cabin Safety and Environmental Systems 
Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 
98198; phone and fax: 206-231-3570; email: susan.l.monroe@faa.gov. Any 
commentary that the FAA receives that is not specifically designated as 
CBI will be placed in the public docket for this rulemaking.

Regulatory Flexibility Act (RFA)

    The requirements of the RFA do not apply when an agency finds good 
cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and 
comment. Because the FAA has determined that it has good cause to adopt 
this rule without notice and comment, RFA analysis is not required.

Costs of Compliance

    Currently, there are no affected U.S.-registered airplanes. For any 
affected airplane that is imported and placed on the U.S. Register in 
the future, the FAA provides the following cost estimates to comply 
with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
              Action                        Labor cost            Parts cost            Cost per product
----------------------------------------------------------------------------------------------------------------
Operational Test..................  4 work-hours x $85 per                  $0  $340 per test cycle.
                                     hour = $340 per test
                                     cycle.
New relays/wiring changes.........  104 work hours x $85 per            11,417  $20,257.
                                     hour = $8,840.
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[[Page 10446]]

    We estimate the following costs to do any necessary system fault 
isolation and replacements that would be required based on the results 
of the operational test. We have no way of determining the number of 
aircraft that might need these actions:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Perform system fault isolation and replace      10 work-hours x $85 per hour =                $0            $850
 faulty component.                               $850.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. ``Subtitle VII: Aviation Programs'' 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866, and
    (2) Will not affect intrastate aviation in Alaska.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2021-01-07 The Boeing Company: Amendment 39-21383; Docket No. FAA-
2020-1109; Product Identifier 2020-NM-067-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective March 9, 2021.

(b) Affected ADs

    This AD affects AD 2016-04-06, Amendment 39-18400 (81 FR 9756, 
February 26, 2016) (``AD 2016-04-06'').

(c) Applicability

    This AD applies to The Boeing Company Model 737-700 airplanes, 
certificated in any category, having line numbers (L/Ns) 481, 545, 
684, 979, 1089, 1211, and 1223.

(d) Subject

    Air Transport Association (ATA) of America Code 2120, Air 
Distribution System.

(e) Unsafe Condition

    This AD was prompted by a determination that a repetitive test 
is needed to assess the components on airplanes equipped with a 
certain air distribution system configuration. The FAA is issuing 
this AD to address latent failures of the equipment cooling system 
and low pressure environmental control system, which, in combination 
with a cargo fire event, could result in smoke in the flight deck 
and/or main cabin, and possible loss of aircraft control.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Repetitive Operational Tests and Corrective Actions

    At the applicable times identified in paragraph 1.E., 
``Compliance'' of Boeing Alert Service Bulletin 737-26A1137, 
Revision 2, dated January 27, 2020, except as required by paragraph 
(i) of this AD, do the test to verify correct operation of the smoke 
clearance mode of the equipment cooling system and low pressure 
environmental control system, and do all applicable corrective 
actions, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-26A1137, Revision 2, dated January 
27, 2020. Do all applicable corrective actions before further 
flight. Repeat the test thereafter at intervals not to exceed 9,000 
flight hours.

(h) Concurrent Requirements

    Before or concurrently with accomplishing the initial 
operational test required by paragraph (g) of this AD, install new 
relays and change the wiring to the environmental control system, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-26A1122, Revision 3, dated January 31, 2020. 
When the actions required by this paragraph are performed, the 
installation and changes specified in paragraph 1.B. ``Concurrent 
Requirements'' of Boeing Alert Service Bulletin 737-26A1122, 
Revision 3, dated January 31, 2020, must also be done.

(i) Exceptions to Service Information Specifications

    Where Boeing Alert Service Bulletin 737-26A1137, Revision 2, 
dated January 27, 2020, uses the phrase ``the R02 issue date of SB 
737-26A1137,'' this AD requires using ``the effective date of this 
AD.''

(j) Terminating Action for AD 2016-04-06

    As of the effective date of this AD, for the airplanes 
identified in paragraph (c) of this AD only, the requirements of AD 
2016-04-06 are terminated.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (l) of this AD. Information may be 
emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the

[[Page 10447]]

Manager, Seattle ACO Branch, FAA, to make those findings. To be 
approved, the repair method, modification deviation, or alteration 
deviation must meet the certification basis of the airplane, and the 
approval must specifically refer to this AD.
    (4) For service information that contains steps that are labeled 
as Required for Compliance (RC), the provisions of paragraphs 
(k)(4)(i) and (ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(l) Related Information

    For more information about this AD, contact Susan L. Monroe, 
Aerospace Engineer, Cabin Safety and Environmental Systems Section, 
FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; 
phone and fax: 206-231-3570; email: susan.l.monroe@faa.gov.

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Service Bulletin 737-26A1122, Revision 3, dated 
January 31, 2020.
    (ii) Boeing Alert Service Bulletin 737-26A1137, Revision 2, 
dated January 27, 2020.
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability 
of this material at the FAA, call 206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on December 30, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-01823 Filed 2-19-21; 8:45 am]
BILLING CODE 4910-13-P


